Bug 1536023

Summary:	Cannot restore disk layout of software raid devices when some device is missing
Product:	Red Hat Enterprise Linux 7	Reporter:	Renaud Métrich <rmetrich>
Component:	rear	Assignee:	Pavel Cahyna <pcahyna>
Status:	CLOSED ERRATA	QA Contact:	David Jež <djez>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	7.4	CC:	djez, ovasik, pcahyna
Target Milestone:	rc
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	rear-2.4-1.el7	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2018-10-30 11:43:19 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Renaud Métrich 2018-01-18 13:34:59 UTC

Description of problem:

If a software raid device is in degraded state at the time of the "rear mkrescue" creation (e.g. a device has been removed from a RAID1 array), the disk layout restoration will fail with following error seen in the log:

mdadm --create /dev/md127 --force --metadata=1.2 --level=raid1 --raid-devices=2 --uuid=a0fc5637:fdf5dafa:a345e010:83293548 --name=boot /dev/sdb1
+++ echo Y
mdadm: You haven't given enough devices (real or missing) to create this array


This is indeed due to the missing device (/dev/mapper/mpatha1)


Version-Release number of selected component (if applicable):

rear-2.00-3.el7_4.x86_64


How reproducible:

ALWAYS


Steps to Reproduce:
1. Set up a software raid with 2 devices in RAID1
2. Remove one of the device (/dev/sda1)
3. Create rear rescue image
4. Try restoring the disk layout

Actual results:

initramfs's /var/lib/rear/layout/disklayout.conf will contain:

raid /dev/md127 metadata=1.2 level=raid1 raid-devices=2 uuid=a0fc5637:fdf5dafa:a345e010:83293548 name=boot devices=/dev/sdb1
...

leading to mdadm complaining and aborting.


Additional info:

Issue to be created in Upstream as well

Comment 4 Pavel Cahyna 2018-06-27 16:25:09 UTC

1536023 merged upstream in 2.4/643d778e6a39a869bd9e5962436285fbb44fa71c

Comment 9 errata-xmlrpc 2018-10-30 11:43:19 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2018:3293